WATER ? please help explain this

I have a question about freezing water. In a water line, when the water freezes The pipe will burst. There isn't energy being put into the water it is actually being taken out of the "system". It produces a great force to burst the pipe. To me this defies the Laws of conservation of energy.

The law of conservation of energy is an empirical law of physics. It states that the total amount of energy in an isolated system remains constant over time (is said to be conserved over time). A consequence of this law is that energy can neither be created nor destroyed: it can only be transformed from one state to another. The only thing that can happen to energy in a closed system is that it can change form: for instance chemical energy can become kinetic energy.

This is from wikipedia

When a force is create it is a form of energy. If I took a box that can expand, filled it with water, then hooked up an assembly of some kind to use this force to create energy the water should experience a loss of mass or should show some temperature change.

I have several questions:
1. Does it take energy to remove heat from water? I know there are freezers and such, but I mean in nature does it take energy to freeze a pond?
2. how much force is need to burst these pipes and can It be accounted for as to where the energy to do this comes from.
3. I know that water expands due to its molecular structure when it freezes. How can it expand when its physical state is being lowered. As ice it is a certain volume then it goes to water, the volume shrinks then to a gas the volume expands? also is there anyother compound that does this.

I am a construction worker, I don't know if this is a stupid question. thanks for any help understanding this


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reply to post by jlafleur02


It's a good question, it certainly does seem counter intuitive.

There are two parts to the answer, I will attempt the first bit as it is easier

Burst pipes are not usually actually caused by the Ice expanding, rather the Ice forms a blockage that traps water between it and the fawcet, as the ice expands it increases the water pressure in that bit of pipe hundreds of times over until the pipe bursts, if you leave a tap dripping in the freezing weather then your pipes won't burst so much

reply to post by davespanners

Very true but where does the energy come from to increase the pressure? The alignment of water molecules is a motion that must create a force to be completed, a force that creates the pressure. I know about opening your spigots to relieve pressure. I actually get a lot of calls from people who have this happen to them. One person who had a rental property decide to shut off the heat to save money in a property that was vacant. All there pipes burst. It cost a lot of money to repair that. Walls must be opened, insulation and sheetrock replaced flooring destroyed. Its almost like taking your roof off during a rainstorm. Basically recks a house.

reply to post by jlafleur02


Hmm.. We need a chemist

I would think that water in a liquid state actually contains energy in the form of heat, that is what is keeping it in a liquid state so the energy comes from within the water.

Ughh It's a really confusing question,

reply to post by jlafleur02


Here is an article that explains it a little better link

This unusual behavior has its origin in the structure of the water molecule. There is a strong tendency to form a network of hydrogen bonds, where each hydrogen atom is in a line between two oxygen atoms. This hydrogen bonding tendency gets stronger as the temperature gets lower (because there is less thermal energy to shake the hydrogen bonds out of position). The ice structure is completely hydrogen bonded, and these bonds force the crystalline structure to be very "open", as shown in the following picture:

reply to post by davespanners


I don't agree davespanners.

It's a very interesting question the OP has asked, and one that isn't as easy to explain as you suggest.

A simple experiment to prove it is not water pressure backing up behind an ice blockage in the pipe, is this.

Take a plastic pop bottle, fill it to the very brim with water, put the cap on, and freeze it.

There is no water pressure, no blockage increasing the pressure of backed up water in the tap etc...yet there will be sufficient energy due to the freezing and expansion of the water to burst the pop bottle or force the tight cap off....

The example you posted about hydrogen bonds etc suggests that the freezing process is responsible for exerting an energy upon the bonds of the water molecule, and effectively causing them to be spaced further apart, hence the expansion.

This still doesn't answer the question of where the energy comes from to achieve this?

Thinking about it, if a quantity of energy is in the liquid water stored as heat, then it could be that this heat energy is not being drawn off to the surrounding atmosphere, as much as it is being converted to a 'separation energy', forcing the atoms further apart, causing expansion of the lattice.

reply to post by spikey


Thats true, Ice does indeed expand with enough pressure to burst things by itself and is responsible for some pipes bursting.
I just indicated that the ice usually isn't the reason for pipes bursting, not that it can't be

As for the molecular part, as it says in the quote it is the energy that is stopping the hydrogen molecules from forming this strong bond that is found in ice by "shaking them around" once the energy is taken out of the system the bonds form

As I said It's a hard question and I am not a chemist

I can do nothing to clarify this any further, but want to say that my mind is officially blown. I will be very interested to see what the resident experts might have to say here.

reply to post by davespanners


Nah, me neither.

Interesting though isn't it.

We know that atoms vibrate faster the more they are heated, so the 'jiggling atoms' not being able to form the type of hydrogen bonds found when heat energy has been removed is a good explanation.

Perhaps waters natural state is ice, and the atoms always try to return to the frozen state, but it's the application of heat energy, that keeps water liquid, and in an 'unnatural' state as it were.

But it's still true though, that if the heat energy is removed, causing the water to change it's molecular bonding to form ice, that it still has enough energy to burst through solid metal pipes.

Curious isn't it.

reply to post by spikey


I have another question related to this, if i were to place your frozen pop bottle into a compression chamber and squeeze it exreamly hard wouldnt that energy from the squeeze result in liqufying the H2O again? I think once it is a liquid again it cannot be squeezed futher?

reply to post by bigfatfurrytexan


Who is an expert on this kind of thing? Can we somehow summon them to appear?
I'm not even sure a Chemist is the right person now, I guess a physicist would be more useful or an iceologist

I think that force has to do with the expansion of ice. Here are 2 links that may help you.

Bursting Waterpipe There is a video included to demonstrate the effect.

"One of water's most remarkable properties is that it expands when it freezes to a volume that is always 10% greater than in the liquid state. In other words, 10 cups of water put into the freezer is going to turn into 11 cups of ice when it freezes.

Here is another link that show how strong that force is.

In any case, water expands strongly when it freezes, and whether it is 114,000 psi, or 100,000 psi or even 50,000 psi, it can burst pipes and disrupt foundations.

Force of Freezing water

Hope that helps

Peace

being captain obvious here.... pipes bursting in the winter is from the pressure of water behind the ice blockage that keeps building up (17-20psi) and the contraction of the steel in the pipe making it smaller.

Now freezing water in a sealed bottle doesn't the air have to move somewhere? also the contraction of the bottle itself.

Originally posted by coffeesniffer
reply to post by spikey

 

I have another question related to this, if i were to place your frozen pop bottle into a compression chamber and squeeze it exreamly hard wouldnt that energy from the squeeze result in liqufying the H2O again? I think once it is a liquid again it cannot be squeezed futher?

I know during chemistry in high school my teacher put water in a beaker and lower the preassure in the system to a certain number and when she put her hand on it the water boiled. Also water under pressure will have a lower freezing point.

The energy is already in the water. A temperature above 0K means there is thermal energy. The freezing point of water is about 273K. You can calculate the energy by E=1/2kT. When the water is trapped, this energy generates the force needed to make something crack. After the pressure is released, the temperature will drop, and energy is conserved. This is actually also the reason why ice is slippery. When you put pressure on ice it will warm up and melt so that you create a very small layer of water. Same principle by the other way around.

reply to post by Seed76


They were some really interesting links!

114,000 psi is quite phenomenal!

Originally posted by -PLB-
The energy is already in the water. A temperature above 0K means there is thermal energy. The freezing point of water is about 273K. You can calculate the energy by E=1/2kT. When the water is trapped, this energy generates the force needed to make something crack. After the pressure is released, the temperature will drop, and energy is conserved. This is actually also the reason why ice is slippery. When you put pressure on ice it will warm up and melt so that you create a very small layer of water. Same principle by the other way around.

Actually ice is slippery due to the weak bonds of the molecules on the outer edge of the ice itself nothing to due with the ice melting.

heres a link its a very recent discovery. The thin film of water is due to only part of the water molecule have a bond. I saw it on tv may nat geo channel
slippery ice

Originally posted by coffeesniffer
reply to post by spikey

 

I have another question related to this, if i were to place your frozen pop bottle into a compression chamber and squeeze it exreamly hard wouldnt that energy from the squeeze result in liqufying the H2O again? I think once it is a liquid again it cannot be squeezed futher?

I think i see where you're going with this, and it's an (again) an interesting concept.

If the frozen pop bottle was compressed, i guess heat/friction would be generated and could melt the ice (jiggling the atoms and changing the bonds), if you compressed the now liquid water further, more heat would be generated and i guess steam would be the result.

I'm thinking...what would happen if you had a couple of miles in your back yard (yeah, i know but this is hypothetical), and laid down a series of short tubes, say a foot long by a few inches diameter, half way inside the tube, you had a piston, and the other half was filled with water.

Lay these tubes, side by side (or end to end) and attach the pistons to hydraulic lines..when the water froze, it would put pressure on the piston, which would pressurise the hydraulic system....from that we would get work from essentially a system that has had the energy (heat) removed...wouldn't we?

reply to post by davespanners


Yes indeed. It´s fascinating the amount of force that is produced by the expansion of water has when it freezes.

Peace

Originally posted by davespanners
reply to post by bigfatfurrytexan

 

Who is an expert on this kind of thing? Can we somehow summon them to appear?
I'm not even sure a Chemist is the right person now, I guess a physicist would be more useful or an iceologist

Well, we don't have a Phage right now.

Maybe Buddhasystem? Matyas is someone I know could elucidate this a little. Not everyone is aware of his genius because he tends to whisper.